Transient liquid phase material bonding and sealing structures and methods of forming same

Abstract

A method of forming a bonding element including a first transient liquid phase (TLP) bonding element including a first material and a second material, the first material having a higher melting point than the second material, a ratio of a quantity of the first material and the second material in the first TLP bonding element having a first value, and a second TLP bonding element including the first material and the second material, a ratio of a quantity of the first material and the second material in the second TLP bonding element having a second value different from the first value.

What is claimed is: 
     
       1. A method of forming a wireless module including a device and a substrate, the method comprising:
 forming a first bonding element on a surface of one of the device and the substrate, the first bonding element including a first alloy of a first material and a second material, the first material having a higher melting point than the second material, a ratio of a quantity of the first material and the second material in the first bonding element having a first value; 
 forming a second bonding element on a surface of one of the device and the substrate, the second bonding element including a second alloy of the first material and the second material, a ratio of a quantity of the first material and the second material in the second bonding element having a second value different from the first value; 
 forming at least one strut on a surface of one of the device and the substrate, the at least one strut including a third alloy of the first material and the second material, the at least one strut connecting the first bonding element and the second bonding element; 
 contacting the device with the substrate with the first bonding element and the second bonding element disposed between the device and the substrate and in contact with both the device and the substrate; and 
 heating the first bonding element and the second bonding element at a temperature and time sufficient for the first material and the second material in the first bonding element and the second bonding element to interdiffuse and form a first bonded element and a second bonded element. 
 
     
     
       2. The method of  claim 1  wherein the device is one of a power amplifier, a low noise amplifier, and an antenna switch module. 
     
     
       3. The method of  claim 1  wherein the ratio of the quantity of the first material and the second material in the first bonded element is determined by a distance between the first bonded element and a third bonded element. 
     
     
       4. The method of  claim 1  wherein forming the first bonding element includes forming the first bonding element on the surface of the substrate and surrounding a device disposed on the substrate. 
     
     
       5. The method of  claim 4  wherein the forming the second bonding element includes forming the second bonding element on the surface of the substrate and surrounding the first bonding element. 
     
     
       6. The method of  claim 4  wherein forming one of the first bonding element or the second bonding element includes forming a protrusion within the first bonding element or second bonding element, the protrusion being configured to direct molten liquid escaping from the one of the first bonding element or the second bonding element away from the device. 
     
     
       7. The method of  claim 1  wherein forming one of the first bonding element or the second bonding element includes forming a protrusion within the first bonding element or second bonding element, the protrusion being configured to direct molten liquid escaping from the one of the first bonding element or the second bonding element toward the other of the first bonding element or the second bonding element. 
     
     
       8. The method of  claim 1  wherein forming the first bonding element includes forming the first bonding element on the surface of the substrate and having a closed geometric shape surrounding a portion of the substrate upon which no transient liquid phase structure is disposed. 
     
     
       9. The method of  claim 8  wherein forming the second bonding element includes forming the second bonding element on the surface of the substrate and having a closed geometric shape surrounding the first bonding element, the second bonding element being at least partially separated from the first bonding element by a second portion of the substrate upon which no transient liquid phase structure is disposed. 
     
     
       10. The method of  claim 1  further comprising forming a third bonding element including the first material and the second material, a ratio of a quantity of the first material and the second material in the third bonding element having a third value, the third value being between the first value and the second value, the third bonding element being disposed on the substrate and having a closed geometric shape and one of surrounding or being surrounded by the first bonding element, the third bonding element being at least partially separated from the first bonding element by a portion of the substrate upon which no transient liquid phase structure is disposed. 
     
     
       11. A method of forming at least one bonding structure, the method comprising:
 forming a first bonding element on a first portion of a substrate, the first bonding element including a first material and a second material, an amount of the first material and an amount of the second material being present in the first bonding element in a first ratio, the first bonding element having a closed geometric shape surrounding a portion of the substrate; 
 forming at least one second bonding element on a second portion of the substrate, the at least one second bonding element including the first material and the second material, the amount of the first material and the amount of the second material being present in the at least one second bonding element in a second ratio different from the first ratio, the second bonding element having a closed geometric shape surrounding the first bonding element, the second bonding element being at least partially separated from the first bonding element by a second portion of the substrate upon which no bonding element is disposed; and 
 heating the first bonding element and the at least one second bonding element to form the at least one bonding structure. 
 
     
     
       12. The method of  claim 11  wherein forming the first bonding element includes forming the first bonding element with a protrusion of a one of the first material and the second material having a higher melting temperature than the other of the first material and the second material, the protrusion configured to direct molten material from the first bonding element toward the second bonding element. 
     
     
       13. The method of  claim 11  wherein forming one of the first bonding element or the second bonding element includes forming the one of the first bonding element or the second bonding element with a ratio of the first material to the second material selected to form a stoichiometric intermetallic alloy of the first material and the second material. 
     
     
       14. The method of  claim 11  wherein forming one of the first bonding element or the second bonding element includes forming the one of the first bonding element or the second bonding element with a ratio of the first material to the second material selected to form a region in the one of the first bonding element or the second bonding element that is richer in the second material than a stoichiometric intermetallic alloy of the first material and the second material. 
     
     
       15. The method  claim 11  further comprising hermetically sealing a device within a cavity at least partially defined by the at least one bonding structure. 
     
     
       16. The method of  claim 15  wherein hermetically sealing the device within the cavity includes sealing a radio frequency (RF) device within the cavity. 
     
     
       17. The method of  claim 16  wherein the substrate is included in an RF device module and sealing the radio frequency device within the cavity includes sealing the RF device within a cavity defined in the RF device module. 
     
     
       18. The method of  claim 17  further comprising forming an RF device including the RF device module. 
     
     
       19. The method of  claim 11  further comprising forming an electronic device including the substrate. 
     
     
       20. The method of  claim 11  further comprising forming an electronic device including at least one component bonded to the substrate with the at least one bonding structure.